<!DOCTYPE html>
<html>
    <head>
        <meta charset="utf-8">
        <title>CSS引入</title>
        <!-- 引入外部样式表style1.css -->
        <link rel="stylesheet" href="style1.css" type="text/css">
        <style>
            /* 导入外部样式表 */
            @import url("style2.css");
            /*内部样式表*/
            nav ul{list-style: none;}
            nav li{float:left;margin-right: 20px;}
        </style>
    </head>
    <body>
        <header style="border:1px solid #ccc;color:blueviolet;font-size:2em;font-family: 'Gill Sans', 'Gill Sans MT', Calibri, 'Trebuchet MS', sans-serif">
            &lt;header&gt;标签内容
        </header>
        <nav>
            <ul>
                <li>第一项</li>
                <li>第二项</li>
                <li>第三项</li>
            </ul>
        </nav>
        <article>
            文章内容
        </article>
        <footer>copyright&copy;18大数据1 班</footer>
    </body>
</html>